Abstract: A moving object detecting apparatus includes: a transmitting/receiving unit for radiating an ultrasonic wave and receiving a reflective wave reflected from an object present in a monitoring space; a phase detection circuit for mixing reference signals with a reflective signal and obtaining a pair of Doppler signals each having an amplitude depending on a phase difference from the reference signal, each of the Doppler signals having a different phase from each other; a rotation angle calculation unit for calculating a rotation angle; a cumulative addition unit for accumulating the rotation angle; and a comparison unit for comparing the accumulated rotation angle with a threshold value. In the moving object detecting apparatus, a single ultrasonic vibrator is commonly used in the transmitting unit and the receiving unit.

Abstract: A moving object detecting apparatus includes: a transmitting/receiving unit for radiating an ultrasonic wave and receiving a reflective wave reflected from an object present in a monitoring space; a phase detection circuit for mixing reference signals with a reflective signal and obtaining a pair of Doppler signals each having an amplitude depending on a phase difference from the reference signal, each of the Doppler signals having a different phase from each other; a rotation angle calculation unit for calculating a rotation angle; a cumulative addition unit for accumulating the rotation angle; and a comparison unit for comparing the accumulated rotation angle with a threshold value. In the moving object detecting apparatus, a single ultrasonic vibrator is commonly used in the transmitting unit and the receiving unit.

Abstract: An optical radio system includes a host device, an end device, and a repeater. The host device and the end device communicate with each other via the repeater by use of optical radio. The repeater includes a section for receiving a first light signal from one of the host device and the end device, a section for converting the received first light signal into a first electric signal, a section for frequency-converting the first electric signal into a second electric signal, and a section for generating a second light signal in response to the second electric signal and transmitting the generated second light signal. The repeater also includes a section for demodulating one of the first electric signal and the second electric signal into a baseband signal, a section for detecting a quality of the baseband signal, and a section for enabling transmission of the second light signal only when the detected quality of the baseband signal is equal to or greater than a predetermined quality.

Abstract: A moving object detecting device is arranged for detection in time series of an angle of respective received-wave signals at every moment with respect to basic axes in a vector plane, the basic axes being a pair of intermediate signals obtained by converting frequency deviation components of the received-wave signals responsive to incident on a wave receiver of reflected waves of radiated energy by a wave radiator from an object moving in a supervisory zone. Such moving object can be thereby detected at a high precision, irrespective of how quickly or slowly it moves within the zone.

Abstract: A composite type crime preventive sensor processes output detection signals from a plurality of sensor units of mutually different detection systems for ranking the signals into a plurality of grades depending on signal level, and provides an intruder detection signal when a sum of ranked level values is above a preset reference value, whereby any risk of alarm failing and erroneous alarming can be effectively minimized.

Abstract: An electrostatic transducer which includes a vibrating membrane provided between a fixed electrode and a movable electrode to which electric signals are applied. The transducer further includes a plurality of depressions provided concentrically with a center of the fixed electrode in a surface of the fixed electrode which is in contact with the vibrating membrane and a plurality of through openings corresponding with the plurality of depressions further provided in the fixed electrode whereby the resonant frequency of the electrostatic transducer is reduced and the conversion efficiency of electric signals to sound pressure is increased.

Abstract: A duplicator in which analog signals recorded on a master or like source tape are transferred to digital discs after conversion into digital form and the digital signals thus recorded on the digital discs are then transferred to slave tapes after reconversion into analog form.

Abstract: An echo-type switch using ultrasonic wave for detecting any object present in a predetermined area with reliable operation irrespective of environmental variations or foreign waves. After the wave is once radiated, the detection is suspended for a fixed time period T.sub.1 and presence or absence of reflected wave received is confirmed during another period T.sub.2. If reflected wave is received in the period T.sub.2, this period is again set for further confirming if the received wave continues and, until absence of the received wave is confirmed after several times of the waves received during the period T.sub.2, next ultrasonic wave is not radiated. Only in case the reflected wave received continues for more than two of the periods, the presence of the object to be detected in the area is indicated.

Abstract: This invention provides an ultrasonic wave watching device for detecting a moving object wherein an ultrasonic wave signal generated by an oscillator is transmitted from a transmitter, reflected signals from a stationary object and moving object are received by a receiver and the variation with time of the phase difference between these received signals and the transmitted signal is detected to determine the presence and moving direction of the moving object.

Abstract: An ultrasonic wave horn adaptable to any desired radiation pattern varying in length-to-breadth ratio of intended detecting area. The horn comprises at least a horn body having gradually expanding caliber from a constricted throat to an expanded opening which is of a flat shape with an unequal length-to-breadth ratio, and an ultrasonic wave generating source of which wave emitting side is disposed adjacent the constricted throat of the horn body, wherein the constricted throat of the horn body is also of a flat shape having an unequal length-to-breadth ratio and the respective major axes of the flat-shaped constricted throat and expanded opening of the horn body are in a relation of intersecting each other at right angles.